In an image forming device such as a copier or a printer which employs an electrophotography, light for the writing of electrostatic latent images is irradiated from an optical scanner onto a photoreceptor (an image carrier) uniformly charged by a charging means. Electrostatic latent images are formed on the photoreceptor. Thereafter, the respective electrostatic latent images are developed by a developing device through the use of a tonner and are manifested as tonner images.
The optical scanner accommodates a scanning optical system which emits light for the writing of electrostatic latent images toward the photoreceptor. The optical scanner includes an emission port through which light is emitted from the scanning optical system and a dust-proof glass (a cover glass) which covers the emission port. For example, a color image forming device includes four emission ports and four dust-proof glasses covering the emission ports, which are provided in one-to-one correspondence to four colors of magenta (M), cyan (c), yellow (Y) and black (B).
In this optical scanner, optical properties grow worse if dirt or dust adheres to the surfaces of the dust-proof glasses. For that reason, it is necessary to periodically clean the surfaces of the dust-proof glasses. There has been proposed an automatic cleaning mechanism for periodically cleaning the surfaces of the dust-proof glasses. For example, there has been proposed an automatic cleaning mechanism configured to move four cleaning members in a long-side direction (longitudinal direction) of four cover glasses using four screw shafts so that the four cover glasses can be cleaned at the same time.
However, the aforementioned automatic cleaning mechanism is configured such the four cover glasses are cleaned at the same timing as the four cleaning members are moved by a single motor. Therefore, the load applied to the motor at that time becomes higher. It is therefore necessary to employ a high-output expensive motor. This becomes one cause of escalating device costs.
In view of the circumstances mentioned above, it is an object of the technology of the present disclosure to provide an optical scanner capable of reducing a load applied to a motor during a cleaning process and eventually making it possible to use a relatively cheap motor